IS 14458-1: Guidelines for retaining wall for hill area, Part 1: Selection of type of wall

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IS 14458-1 (1998) : Guidelines for retaining wall for hill
area. Part 1: Selection of type of wall [CED 56: Hill Area
Development Engineering]

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IS 14458 (Part 1) : 1998

. ( Reaffirmed 2002 )

Indian Standard

RETAINING WALL FOR HILL AREA —

GUIDELINES

PART 1 SELECTION OF TYPE OF WALL

ICS 93.020

©BIS 1998

BUREAU OF INDIAN STANDARDS

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

May 1998 Price Group 4

Hill ^rea Development Engineering Sectional Committee, CED 56

FOREWORD

This Indian Standard (Part 1) was adopted by the Bureau of Indian Standards, after the draft finalized by the
Hill Area Development Engineering Sectional Committee had been approved by the Civil Engineering Division
Council.

Retaining wall is a structure used to retain backfill and maintain difference in the elevation of the two ground
surfaces. Retaining wall may be effectively utilized to tackle the problem of landslide in hill area by stabilizing
the fill slopes and cut slopes.

From the initial construction cost considerations, one metre of extra width in filling, requiring retaining walls,
costs much more than constructing the same width by cutting inside the hill. Similarly the cost of a breast wall
is several times more than a non-walled cut slope. However, considering maintenance cost, progressive slope
instability and environmental degradation from unprotected heavy excavations, the use of retaining walls on hill
roads and terraces becomes essential. This standard (Part 1 )-is, therefore, being formulated to provide necessary
guidance in selection of retaining walls for stability of hill slopes, the other parts of the standard being:

Part 2 Design of retaining/breast walls

Part 3 Construction of dry stone walls

Part 4 Construction of banded dry stone walls

Part 5 Construction of cement stone walls

Part 6 Construction of gabion walls

Part 7 Construction of RCC crib walls

Part 8 Construction of timber crib walls

Part 9 Design of RCC cantilever wall/buttressed
walls/L-type walls

Part 10 Design and construction of reinforced earth retaining walls

In the formulation of this standard, considerable assistance has been provided by International Centre for
Integrated Mountain Development, Kathmandu. Assistance has also been derived from Mountain Risk
Engineering Handbook.

The composition of technical committee responsible for the formulation of this standard is given at Annex A.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,
observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with
IS 2 : 1960 *Rules for rounding off numerical values {revised)\ The number of significant places retained in
the rounded off value should be the same as that of the specified value in this standard.

IS 14458 (Part I) : 1998

Indian Standard

RETAINING WALL FOR HILL AREA

GUIDELINES

PART 1 SELECTION OF TYPE OF WALL

1 SCOPE

This standard (Part 1) covers the guidelines for selec-
tion of various retaining walls to suit the site condi-
tions, for the purpose of imparting stability to the
slopes in hill areas.

NOTE — The retaining walls are normally not intended to
stabilize slope failures. They are mainly meant to support the
active or passive earth pressure from the assumed failure wedge
above the base of the wall. The stabilization of existing or
probable failure planes caused by landslides, Hows and faUs
require separate treatment and specific design approaches. Only
the fill slopes and cut slopes could be stabilized/retained by
retaining walls.

2 CLASSIFICATION

2.1 The retaining walls shall be classified on the basis
of type of construction and mechanics of behaviour
(seeVig. 1) as follows:

a) Gravity walls

b) Tie back walls

c) Driven cantilever walls

d) Reinforced earth walls

e) RCC walls

2,2 The classification of retaining walls with respect
to their design and probable behaviour of construction
medium may be as follows:

a) Bin walls

i) Rectangular
ii) Circular
iii) Cross tied

b) Crib walls

i) Concrete crib
ii) Timber crib

c) Gabions walls and wire crated/sausage walls

d) Cement masonry walls

e) Dry^tone masonry walls

f) Drum walls

g) Reinforced backfill walls

ORIGINAL GROUND y
PROFILE -x^^

iU-*ASSUMED .
/ FAILURE PLANE

1(a) GRAVITY WALL

WALL PANELS—*

ASSUMED FAILURE
PLANE

^E ^

ANCHORS-

EARTH ANCHORS
IN BACK-FILL

BED ROCK

GROUTED ANCHOR

1(b) TIE BACK WALL
Fig. 1 Different Types of Retaining Walls — {Continued)

I

IS 14458 (Parti): 1998

TIMBER
LOGGtNO

ASSUMED FAILURE
PLANE

/ WEATHERED
ROCK AMD SOIL

BED ROCK

1(c) DRIVEN CANTILEVER WALL

-ASSUMED FAILURE
PLANE

HEAVY
SURCHARGE

REINFORCING
STRAPS

1(d) REINFORCED EARTH WALL

1(e) RCC WALLS

Fig. 1 Different Types of Retaining Walls

i) Reinforced earth
ii) Fabric
h) Anchored walls

i) Horizontal sheet pile
ii) Vertical sheet pile
iii) H-pile, timber logged
j) RCC walls
i) Cantilever
ii) L-type
iii) Buttressed wall
iv) Frame retaining walls

3 SELECTION OF TYPE OF WALl^

3.1 In general, the choice of wall depends on local
resources, local skill, hill slope angle, foundation
conditions, slope of backfill, compatibility of materials
and scismicity of the region {see Tables 1 and 2).
However, the guidelines given in 3.1.1 to 3.1.14 shall
be considered for selection of the type of retaining wall
to be constructed for the purpose of imparting stability
to the slopes in hill area.

3.1.1 For hilly roads, being of low volume, walls may
not be designed for earthquake forces. It is economical
to repair failed walls after earthquake.

3.1.2 Earthquake considerations lead to excessive
wall dimensions. High walls may, therefore, be
avoided by alternative geometric designs of roads and

terraces unless justified by risk analysis. Walls with
dip at the base towards hillside will reduce the base
width in seismic areas.

3.1.3 Front battered retaining walls are many times
more expensive than back battered wdls in steep hilly
areas.

3.1.4 A retaining wall on a thin talus slope may not
be able to prevent the failure of entire talus slope
during monsoon because of the quick rise of water
table above the relatively impervious bed rock.

3.1.5 The construction of series of retaining walls one
above another on an unstable or marginally stable
slope shall be avoided as it adds more pressure on the
lower waUs destabilizing the slope contrary to the aim
of stabilizing the slope. In such cases, unstable slope
shall be stabilized by afforestation, surface/sub-
surface drainage system, etc.

3.1.6 Improper backfill and poor drainage behind the
wall involve complicated drainage conditions which
are normally not considered in normal design. Proper
drainage behind the walls shall, therefore, be provided.

3.1.7 The practice of undertaking wall construction
after road/hill cutting poses the problem of disposal of
excavated material and loss of top soil that could
otherwise be used for vegetation. Hence during con-
struction of retaining walls, the excavated material
shall be disposed off at suitable identified sites.

IS 14458 (Part 1) : 1998

3.1.8 Breast walls are more economical for cut slopes.
Batter (negative) of the backfill side reduce base width
of the wall significantly.

3.1.9 Dry stone retaining walls, breast walls and tim-
ber crib are economical but least durable, non-ductile
structures. These are most susceptible to earthquake
damages.

3.1.10 Gabion/wire crated walls shall be used in ca^e
of poor foundation or seepage conditions. These can
take considerable differential settlement and some
slope mavement.

3.1.11 Banded dry stone masonry (height < 6 m) and
cement masonry walls are most durable but being non-

ductile structures, are susceptible to earthquake
damages.

3.1.12 Reinforced earth is normally used as reinforced
fill platform for road. Generally it is not used as
preventive method of slope support.

3.1.13 Timber crib, dry stone masonry walls may be
provided for hill slope angle less than 30° and, height
less than 4 m in low volume roads. These are not
suitable for terrace development because of short life.

3.1.14 Cement masonry, RCC walls. Gabion walls
shall be considered for high volume roads, high cut
slopes and terraces. These are also suitable for hill
slope angles from 30° to 60^, where higher walls are
needed.

Table 1 Selection of Retaining Walls

{Clause 3.1)

c/i

Toe protection in case of !
rock/soil

Boulder pitching

Boulder Pitching

N
O
T
E
S

General

Timbers 15 cm (p
with stone rubble
well packed behind
timbers. 10% of all
headers to extend
into filL Ecologi-
cally
unacceptable.

Set stones along
foundation bed. Use
long bond stones.
Hand packed stones
in back fill.

Cement masonry
bands of 50 cm
thickness at 3 m c/c.
Other specifica-
tions as for dry stone
wall.

Weep holes I5x 15
cm size at 1-2 m c/c.
50 cm rubble
backing for

drainage.

Stones to be hand packed. Stone shape
important, blocky preferable to tabular.
Specify maximum/nskiimum stone size.
No weathered stone to be used. Compact
granular back fill in layers (< 15 cm). Use
H type gabion wall.

Granular back fill prefered. Use
geogrid for H <4 m and tensur
grid for H> 4 m. Provide
drainage layer in case of
seepage problems. Specify
spacing of reinforcement grids.

i . Foundations to be stepped up if rock encountered.

2, All walls require durable rock filling of small to medium size.

3. Drainage of wall bases not shown. Provide 15 cm thick gravel layer in case of clayey foundation.

Application

Least durable

Most durable

Can take differential settlement and
slope movement

Huge potential used more as
stable reinforced fill platform
for road rather than preventive
method of slope support.

Non ductile structure most susceptible to earth-
quake damage

Very flexible structures

1 . Design as conventional retaining walls. Assume surcharge on road of 2T/m".

2. Used both as cut slope and fill slopes support. Breast wall is more Economical for
cut slope.

3. Choice of wall depends on local resources, local skill, hill slope angle, fouhdation
conditions and also shape of back fill wedges as illustrated in diagrams and
compatibility of materials.

00

00

Table 2 Selectionof Breast Walls

(Clause 3,1)

Type

Breast Walls/Revetment Walls

Remarks

(7)

L Wall constructioniequiies special skills and
practical labour. Curing of masonry walls
generally not feasible in hills due t<r paucity

of water.

2. The typical dimensions shown leiy both on
well-drained backfill and good foundation
conditions.

3. Detailed design is necessary in case of soil
slopes and walls higher Utsin 6 m and poor
foundation cohditions.

4. Gabion walls should be used in case of poor
foundation/seepage conditions. Tney can
take considerable differential settlen^nt
and some slope movement.

5. Other measures should also be taken, for
example, check drains, turfing, benching of
cut slopes in soft rocks, sealing of cracks,
etc. All preventive measures should be im-
plemented in one season. Total system of
measures is far more effective than in-
dividual measures.

u)

Dry Stone

(2)

Banded Dry
Stone Masonry

(3)

Cement
Masonry

(4)

Gabion

(5)

Horizontal
Drum Wails

(6)

Diagrammatric
cross-section

A.

A

V

\

A-

1

Top width

0.5

0.5

0.5

2

1

Base width

a29H

0.3H

a33H

0.23H

2

i

Front batter

Back batter

3:1

4:1

5:1

3:1

3:1

3 to 5:1

3:1

Inward dip of
foundation

1:3

1:4

1:5

1:3

1:3

1:5

1:3

Foundation
depth below drain

0.5 m

0.5 m

0.5 m

0.5 m

0.5 m

0.5-1 m

0.25 m

Range of height

6 m

4m

3 m

3-8 m

MOm

1-8 m

2.2 m

Hill slope angle

35-60

35-60

35-70

35-60

35

Toe protection
in case of soft
rock/soil

No
pitching

No

No

No

No

General

Pack stone along
foundation bed. Use
bond stones. Specify
minimum stone size.

Cement masonry (1:6)
bands of 0.5 m thick-
ness at 3 m c/c.

Weep holes 15x15 cm
at 1.5-2 m c/c and
grade 1:10. Cement
sand (1:6)

Step in front fece
20-50 cm wide. Other-
wise as for retaining
walls.

Use vertical single dram
for 0.7 m height. Anchor
drum walls on sides.
Fill debris material.

Revetment walls have unifon

n section ai05 m«.75 m thi

ckness for bansr of 2:1 or more

. Section shaped to suit variation and overfareak in rock cut slope. |

Application

Least durable/
economical

UtUe us«J

Most durable/costly

(Juite durabWcostlier
or

Very flexible

Pronrnsing/most economiral
or

Flexible

Non ductile stmctuies most suscepal

:le to earthquake damage.

nt only major erosion, loci

c fall, slope degr^tion parti

cularly where vulnerable s

ttucturesareofrisk.

IS 14458 (Parti): 1998

ANNEX A

(Foreword)

COMMITTEE COMPOSITION

Hill Area Development Engineering Sectional Committee, CED 56

Chairman
Dr Gopal Ranjan

Members
Shri Sheikh Nazir Ahmed
Prof A. K. Chakraborty

-Shri R. C. Lakhera {Alternate)
Chairman-cum-Managing Director

Shri B. B. Kumar {Alternate)
Chief Engineer (Dam Design)

SuPTDG Engineer (Tehri Dam Design Circle) {Alternate)
Chief Engineer (Roads)

SupTDG Engineer (Roads) {Alternate)
Deputy Director General (D & S DTE, DGBR)

Deputy Secretary (T). IRC {Alternate)
Director, HCD (N & W)

Director (Sardar Sarovar) {Alternate)
Dr R. K. Dubey

DrD. S. Upadhyay {Alternate)
Shri Paw an Kumar Gupta

Field Coordinator {Alternate)
ShriT. N.Gupta

Shri J. Sengupta {Alternate)
Shri M. M. Harbola

Shri P. K. Pathak {Alternate)
Dr U. C. Kalita

Shri B. C. Borthakur {Alternate)
ShriS. Kaul
Shri Kireet Kumar
Prof A. K. Maitra

Prof Arvind Krishan {Alternate)
DrG. S. Mehrotra

Shri N. C. Bhagat {Alternate)
Shri P. L. Narula

Shri S. Dasgupta {Alternate)
Shrimati M. Parthasarathy
ShriN. K. Bali {Alternate)
Shri D. P. Pradhan
Shri P. Jagannatha Rao

Shri D. S. Tolia {Alternate)
Dr K.S.Rao
Shri P. K. Sah

Shri J. Gopalakrishna (Alternate)
Shri G. S, Saini
Dr Bhawani Singh

Dr p. C. Jain {Alternate)
Shri Bhoop Singh
ShriR. D. Singh

Dr Sudhir Kumar {Alternate)
Prof C. P. Sinha

Shri D. K. Singh {Alternate)
Shri Lakhbir Singh Sonkhla
Dr p. Srinivasulu

Shri N. Gopalakrishuan {Alternate)

Representing
University of Roorkee, Roorkee

Public Works Department, Jammu & Kashmir
Indian Institute of Remote Sensing, Dehra Dun

Natiohal Buildings Construction Corporation, New Delhi

Uttar Pradesh Irrigation Design Organization, Roorkee

Ministry of Surface Transport, New Delhi

Indian Roads Congress, New Delhi

Central Water Commission, New Delhi

Indian Meteorological Department, New Delhi

Society for Integrated Development of Himalayas, Mussorie

Building Materials & Technology Promotion Council, New Delhi

Forest Survey of India, Dehra Dun

Regional Research Laboratory, Jorhat

Ministry of Railways, New Delhi

G.B. Pant Institute of Himalayan Environment and Development, Almora

School of Planning and Architecture, New Delhi

Central Building Research Institute, Roorkee

Geological Survey of India, Calcutta

Engineer-in-Chief s Branch, Army Headquarters, New Delhi

Sikkim Hill Area Development Board, Gangtok
Central Road Research Institute, New Delhi

IIT, New Delhi

Directorate General Border Roads (D&S), New Delhi

Central Mining Research Institute, Dhanbad
University of Roorkee, Roorkee

Department of^cience and Technology, New Delhi
National Institute of Hydrology, Roorkee

North-Eastem Regional Institute of Water and Land Management,

Assam
Public Works Department, Simla
Structural Engineering Research Centre, Chennai

( Continued on page 8 )

IS 14458 (Parti): 1998

( Continue from page 1 )

Members

SupTDG Surveyor OF Works (NZ)

Surveyor OF Works-I (NZ) (Alternate)

Shri V. Suresh

Shri D. p. Singh (Alternate)

Shri S. C. Tiwari

Shri K. Venkatachalam

Shri S. K. Babbar (Alternate)

DrN. S. Virdhi

Shri Vinod Kumar,
Director (Civ Engg)

Representing
Central Public Works Department, New Delhi

Housing & Urban Development Corporation (HUDCO), New Delhi

U.P. Hill Area Development Board, Lucknow
Central Soil & Material Research Station, New Delhi

Wadia Institute of Himalayan Geology, Dehra Dun
Director General, BIS (Ex-officio Member)

Member Secretaries
Shri T. B. Narayanan
Joint Director (Civ Engg), BIS

Shri Sanjay Pant
Deputy Director (Civ Engg), BIS

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